Effect of interfacial species mixing on phonon transport in semiconductor superlattices

Landry, E. S.; McGaughey, Alan J. H.

doi:10.1103/physrevb.79.075316

Cited by 127 publications

(139 citation statements)

References 53 publications

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“…As shown in Fig. 2 and in previous work, 8 this method is also able to resolve individual thin film thermal conductivities and intrajunction interface thermal conductances when the thin films are sufficiently large. For systems with eight atomic monolayers per film (e.g., Fig.…”

Section: B Nonequilibrium Molecular Dynamicssupporting

confidence: 62%

Thermal conductance of superlattice junctions

McGaughey

2015

AIP Advances

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We use molecular dynamics simulations and the lattice-based scattering boundary method to compute the thermal conductance of finite-length Lennard-Jones superlattice junctions confined by bulk crystalline leads. The superlattice junction thermal conductance depends on the properties of the leads. For junctions with a superlattice period of four atomic monolayers at temperatures between 5 and 20 K, those with mass-mismatched leads have a greater thermal conductance than those with mass-matched leads. We attribute this lead effect to interference between and the ballistic transport of emergent junction vibrational modes. The lead effect diminishes when the temperature is increased, when the superlattice period is increased, and when interfacial disorder is introduced, but is reversed in the harmonic limit. C 2015 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.

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Section: B Nonequilibrium Molecular Dynamicssupporting

confidence: 62%

Thermal conductance of superlattice junctions

McGaughey

2015

AIP Advances

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“…According to experimental [5,6] and modeling [9,19,21] results on Si/Ge superlattices, anharmonic effects are not important for temperatures below 500 K. The anharmonicity would become important when the phonon mean free path due to anharmonicity becomes smaller than the superlattice length L. In the harmonic regime, specular scattering leads to coherent wave effects [29][30][31], while diffuse scattering could destroy coherence.…”

Section: Methodsmentioning

confidence: 99%

“…More recently, a perturbation method based on the Fermi golden rule [11,19,20] was developed, but the method may have limitations on treating interface scattering, as strong scattering may not be captured by perturbation. One alternative approach is to use molecular dynamics simulations [21,22], which do not assume the nature of phonon transport but are classical in nature. Yet the empirical potentials involved in molecular dynamics limit accuracy, and it is difficult to explore the detailed phonon mode behavior.…”

Section: Introductionmentioning

confidence: 99%

Green's function studies of phonon transport across Si/Ge superlattices

2014

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Understanding and manipulating coherent phonon transport in solids is of interest both for enhancing the fundamental understanding of thermal transport as well as for many practical applications, including thermoelectrics. In this study, we investigate phonon transmission across Si/Ge superlattices using the Green's function method with first-principles force constants derived from ab initio density functional theory. By keeping the period thickness fixed while changing the number of periods, we show that interface roughness partially destroys coherent phonon transport, especially at high temperatures. The competition between the low-frequency coherent modes and high-frequency incoherent modes leads to an optimum period length for minimum thermal conductivity. To destroy coherence of the low-frequency modes, scattering length scale on the order of period length is required. This finding is useful to guide the design of superlattices to reach even lower thermal conductivity.

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“…Turney et al 7 suggest that reasonable predictions of relaxation times and thermal conductivity can be made using lattice dynamics calculations up to half of the Debye temperature. Here, we consider SW silicon at a temperature of 300 K, which is less than half of its Debye temperature, 710 K. 30 Details of our lattice dynamics calculations are provided by Turney and co-workers. 5,7,31 …”

Section: Predicting Phonon Properties Using Lattice Dynamics Calcumentioning

confidence: 99%

Cross-plane phonon transport in thin films

Sellan¹,

Turney²,

McGaughey³

et al. 2010

Journal of Applied Physics

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127

114

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We predict the cross-plane phonon thermal conductivity of Stillinger-Weber silicon thin films as thin as 17.4 nm using the lattice Boltzmann method. The thin films are modeled using bulk phonon properties obtained from harmonic and anharmonic lattice dynamics calculations. We use this approach, which considers all of the phonons in the first Brillouin-zone, to assess the suitability of common assumptions. Specifically, we assess the validity of: ͑i͒ neglecting the contributions of optical modes, ͑ii͒ the isotropic approximation, ͑iii͒ assuming an averaged bulk mean-free path, and ͑iv͒ the Matthiessen rule. Because the frequency-dependent contributions to thermal conductivity change as the film thickness is reduced, assumptions that are valid for bulk are not necessarily valid for thin films.

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Effect of interfacial species mixing on phonon transport in semiconductor superlattices

Cited by 127 publications

References 53 publications

Thermal conductance of superlattice junctions

Thermal conductance of superlattice junctions

Green's function studies of phonon transport across Si/Ge superlattices

Cross-plane phonon transport in thin films

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